#include <stdint.h>
#include <msp430.h>
#include "musicdata.h"

#define interrupt(x) void __attribute__((interrupt (x)))

void delay_ms(uint16_t ms) {
    while (ms--)
        __delay_cycles(1000);
}

int16_t freqs[] = { 0x0eee, 0x0bd9, 0x09f7, 0x0bd9 };

uint16_t wavelen[] = { 0, 0, 0 };
uint16_t count[] = { 0, 0, 0 };
uint8_t duty[] = { 1, 1, 1 };
uint8_t toggle[] = { 0, 0, 0 };
uint16_t next;

int main() {
    // Disable watchdog
    WDTCTL = WDTPW | WDTHOLD;

    // 1MHz internal timer
    BCSCTL1 = CALBC1_1MHZ;
    DCOCTL = CALDCO_1MHZ;

    // P2 (XOUT/XIN) as GPIO
    P2SEL = 0x00;
    
    P1OUT = 0x00;
    P1DIR = 0x01; // LED

    P1REN |= 0x08;

    //while (!(P1IN & 0x08)) ;

    // TA0 on P1.1, TA1 on P1.2
    P1SEL |= 0x02 | 0x04;
    P1DIR |= 0x02 | 0x04;

    TACTL = TASSEL1 | TACLR; // SMCLK source for timer
    
    TACCTL0 = OUTMOD_4 | CCIE; // Channel 0 (output mode toggle, enable interrupt)
    TACCTL1 = OUTMOD_4 | CCIE; // Channel 1
    TACCTL2 = OUTMOD_4 | CCIE; // Channel 2

    __enable_interrupt();

    TACTL |= MC1; // Enable timer, continuous mode

    count[0] = 0;
    count[1] = 0;

    for (uint8_t i = 0; i < 5; i++) {
        wavelen[0] = note_wl[i + 40];
        wavelen[1] = note_wl[i + 44];
        wavelen[2] = note_wl[i + 47];
        
        delay_ms(200);
        wavelen[0] = wavelen[1] = 0;
        delay_ms(100);
    }

    TACTL = TACLR;
    P1OUT = 0;

    return 0;
}

#define UPDATE_CHANNEL(n) \
uint16_t wl = wavelen[n]; \
if (toggle[n]) \
    count[n] += wl >> duty[n]; \
else \
    count[n] += wl - (wl >> duty[n]); \
toggle[n] ^= 1; \
TACCR##n = count[n]; \
TACCTL##n &= ~CCIFG;

interrupt(TIMER0_A0_VECTOR) ta0_isr() {
    UPDATE_CHANNEL(0);
}

interrupt(TIMER0_A1_VECTOR) ta1_isr() {
    if (TACCTL1 & CCIFG) {
        UPDATE_CHANNEL(1);
    } else if (TACCTL2 & CCIFG) {
        UPDATE_CHANNEL(2);
    }
}

#undef UPDATE_CHANNEL